Printing press and paper-splicing method for reel stand unit

ABSTRACT

A paper splicing method for a printing press and a reel stand unit that prevents misregistration at a paper-splicing section in the top-to-bottom direction and that enables improvement of printing quality and stable printing are provided. Provided is a printing press including a reel stand unit configured to bond a web fed out from an old reel to a new reel and continuously feed paper by splicing paper from the old reel to the new reel, wherein the distance in the length direction of an overlapping section of the old reel and the new reel spliced by the reel stand unit is smaller than the minimum distance between driving rollers provided in the printing press. The driving rollers are, in particular, the distance between a printing unit and a blanket cylinder.

TECHNICAL FIELD

The present invention relates to a printing press including reel stand units that perform paper splicing while running webs and to a paper-splicing method for reel stand units.

BACKGROUND ART

A web offset press includes reel stand units for supplying paper rolls (reels) composed of rolled webs to printing units (for example, refer to Patent Document 1). Each reel stand unit is configured to hold, for example, three paper rolls. When paper is fed from a first paper roll, a second paper roll is in a paper-splicing preparation state, and a third paper roll is loaded. When the remaining amount of the web on the first paper roll decreases, the web on the second paper roll is spliced. While the web is supplied from the second paper roll, the first paper roll is loaded and prepared for paper splicing. In this way, the web is continuously fed from the reel stand unit to the printing unit.

Splicing is carried out by a paster during continuous operation. FIGS. 5A and 5B illustrate a prepared paper roll. A tape-like sheet member 101 is bonded to the outer edge of a paper roll 100. An adhesive layer is formed on the front surface of the sheet member 101, and a tape-like bonding material 102 is attached to the back side. By attaching the bonding material 102 to the paper roll 100, the paper roll 100 does not unwind during standby.

As shown in FIGS. 6A to 6C, during splicing, running paper 105 of the old reel is attached to the adhesive layer of the sheet member 101 by the paster (not shown). At this time, as a result of the bonding material 102 being torn and the sheet member 101 being separated from the paper roll 100, the paper roll 100 attaches to the running paper 105 and is continuously fed out. Then, the old reel is cut by a cutter provided in the paster, and slicing is completed.

Patent Document 1:

Japanese Unexamined Patent Application, Publication No. 2004-155564

DISCLOSURE OF INVENTION

With such a rotary printing press, it has been discovered that when paper splicing is performed, misregistration occurs in the top-to-bottom direction at the paper-spliced section, sometimes resulting in a phenomenon whereby the printing quality decreases. Furthermore, in some cases, problems such as unstable behavior of the running paper and unstable cutting Occur.

The present invention has been conceived in light of the circumstances described above, and an object thereof is to provide a printing press and a paper splicing method for a reel stand unit that are capable of preventing misregistration in the top-to-bottom direction at the paper-spliced section and that enable an increase in printing quality and stable printing.

As a result of the inventors having carried out extensive investigation on the cause of the above-described problem, it was discovered that when a double-layered spliced web is stretched over two pairs of driving rollers (for example, blanket cylinders of a printing unit, drag rollers provided on the web path, or nipping rollers in a folding unit), the feeding amount changes significantly, causing misregistration in the top-to-bottom direction. This may be caused by an increase in the paper feeding force and paper pulling force due to two sheets of running paper simultaneously contacting the driving rollers of the printing unit, etc., a change in the property of the paper due to the amount of water absorption of and the amount of ink on the running paper being halved, and an increase in rattling of the driving system.

To solve these problems, the following solutions are provided in the present invention.

Namely, a first aspect of the present invention provides a printing press including a reel stand unit configured to bond a web fed out from an old reel to a new reel and continuously feeds paper by splicing paper from the old reel to the new reel, wherein the distance in the length direction of an overlapping section of the old reel and the new reel spliced by the reel stand unit is smaller than the minimum distance between driving rollers provided in the printing press.

A second aspect of the present invention provides a splicing method for a reel stand unit configured to bond a web fed out from an old reel to a new reel and continuously feeds paper by splicing paper from the old reel to the new reel, the method including cutting the old reel after the old reel is bonded to the new reel such that the distance of an overlapping section of the old reel and the new reel is smaller than the minimum distance between driving rollers provided on a path where the web passes until the web is finally cut.

According to the first and second aspects, since the distance in the length direction (tail length) of the overlapping section of the spliced old reel and new reel is smaller than the minimum distance between the driving rollers, a double-layered web does not stretch over two driving rollers simultaneously, and thus stable registration is possible. The driving rollers may be blanket cylinders of a printing unit, impression cylinders, drag rollers provided on the web path, nipping rollers in a folding unit, etc. In general, cutting may be performed such that the distance between specific blanket cylinders in a printing unit is the smallest, and the tail length is smaller than the distance therebetween.

The first aspect employs a configuration in which a cutter configured to cut the old reel spliced to the new reel and a control unit configured to control the cutting timing of the cutter are provided, and the control unit controls the cutting timing of the cutter such that the distance in the length direction of the overlapping section of the old reel and the new reel is smaller than the minimum distance between the driving rollers provided in the printing press.

In this way, the tail length is cut such that it is within an appropriate range by controlling, with the control unit, the cutting timing of the cutter cutting the old reel.

In the above-described configuration, the control unit may determine the cutting timing of the cutter on the basis of at least one of cutter delay time, preparation length, and a cutter-to-brush distance.

In this way, the control unit calculates the cutting time of the cutter for acquiring the target tail length by setting the cutter delay time, preparation length, and a cutter-to-brush distance as parameters.

According to the present invention, since the distance in the length direction of the overlapping section of the spliced old reel and new reel is smaller than the minimum distance between the driving rollers, a double-sheeted web does not stretch over two driving rollers simultaneously, and thus stable registration is possible. Therefore, printing quality can be improved. Moreover, stabilization of the cutting position, stabilization of web conveying and so forth can be realized.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view illustrating the structure, in outline, of a web offset press according to an embodiment of the present invention.

FIG. 2A is a schematic view of an example of a paper-splicing method, illustrating a state before starting the paper-splicing process.

FIG. 2B is a schematic view of an example of a paper-splicing method, illustrating a state before starting the paper-splicing process.

FIG. 2C is a schematic view of an example of a paper-splicing method, illustrating the initial stage of the paper-splicing process.

FIG. 2D is a schematic view of an example of a paper-splicing method, illustrating an intermediate stage of the paper-splicing process.

FIG. 2E is a schematic view of an example of a paper-splicing method, illustrating the later stage of the paper-splicing process.

FIG. 2F is a schematic view of an example of a paper-splicing method, illustrating the post-processing of the paper-splicing process.

FIG. 3 is a perspective view illustrating the condition of a spliced web.

FIG. 4 is a block diagram illustrating cutter control by a web offset press control unit.

FIG. 5A is a perspective view illustrating a preparation processing structure for paper splicing of a web roll.

FIG. 5B is a sectional view, taken from the side, of a web edge section of the web roll in FIG. 5A.

FIG. 6A is a sectional view illustrating the initial stage of a paper splicing process of a web roll.

FIG. 6B is a sectional view illustrating the intermediate stage of a paper splicing process of a web roll.

FIG. 6C is a sectional view illustrating the later stage of a paper splicing process of a web roll.

EXPLANATION OF REFERENCE SIGNS

-   1: reel stand unit -   3: printing unit -   9: web offset press control unit (controller) -   18: cutter

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below with reference to the drawings. This embodiment is an application of the present invention to a offset newspaper rotary press for multi-page duplex printing. FIG. 1 is a schematic view illustrating, in outline, the structure of the entire offset newspaper rotary press with a multi-page duplex printing/multi-color printing unit. The web offset press includes a plurality of reel stand units 1 for supplying webs 7; infeed devices 2 for applying appropriate tension to the webs 7; printing units 3; a web conveying device 5 for conveying the webs 7, after printing, to a folding unit 6, splicing the webs 7, and carrying out printing alignment in the flow direction; the folding unit 6 for cutting and folding the webs 7 into quires and conveying the quires; and a web offset press control unit (controller) 9 for controlling the entire web offset press.

The reel stand unit 1 is configured to hold three paper rolls constituting the webs 7 wound into rolls. When paper is fed from a first paper roll, a second paper roll is in a paper-splicing preparation state, and a third paper roll is loaded. When the remaining amount of the web 7 on the first paper roll decreases, the web 7 on the second paper roll is spliced. While the web 7 is supplied from the second paper roll, the third paper roll is prepared for paper splicing. In this way, the web 7 is continuously fed from the reel stand unit 1 to the printing unit 3.

The infeed device 2 is provided with a dancer roller 21 for carrying out tension control and an infeed drag roller 22 for drawing the web 7 from the reel stand unit 1. The infeed drag roller 22 is configured of a pair of rollers sandwiching the web 7. The dancer roller 21 is held in a slidable manner with an actuator that is not shown in the drawing. For example, when the actuator is an air cylinder, its air pressure is set to correspond to various operating and printing conditions. The air pressure of the air cylinder is variably adjusted when malfunctions, such as an imbalance in the webs during cutting-position adjustment, occur.

The number of units included in the printing unit 3 corresponds to the number of printing colors. In this embodiment, printing units 3 a to 3 d are provided as the printing units 3. The printing units 3 a and 3 b are each provided with four printing units on both sides of the web for printing black, cyan, magenta, and yellow, in this order from the bottom. These colors are mixed to perform color printing. Similarly, the printing units 3 c and 3 d are each provided with two printing units for printing black and one other color.

Describing in outline the structure of the printing unit 3 a as a representative example, the printing units print the four colors of black, cyan, magenta, and yellow on the web 7. Printing on the web 7 means printing in the same area on the web 7 that is continuously flowing. In this way, the colors overlap in the same area to form one image, enabling multicolor printing of the image.

The printing units A to D constituting the printing unit 3 a include devices functioning as various rollers, such as blanket cylinders 24 and plate cylinders 23. Motive energy from a common motor is supplied to these various devices. Ink devices and dampening devices (not shown) are provided around the plate cylinders 23.

These printing units 3 are merely examples, and any appropriate printing units may be employed, such as single-color printing units for carrying out duplex monochrome printing or printing units for carrying out four-color printing on one side and two-color printing on the other side.

The printing units 3 carry out predetermined printing on the webs 7 supplied from the reel stand units 1 and supply the webs 7 to the web conveying device 5. The web conveying device 5 includes many turn bars 51 and is configured to change the running routes of the webs 7 from the printing units 3 such that the stacking order thereof can be changed. The width of the webs 7 is equal to the width of four pages of a regular newspaper. The webs 7 illustrated in the drawing are cut with a slitter at the center in the width direction after printing. Then the two-page-wide web 7 on one side in the width direction is stacked on the two-page-wide web 7 on the other side at the turn bars 5. In this way, the web 7 entering the folding unit has eight layers, and 32-page printed material, i.e., eight sheets of newspaper each having four pages (two pages on each side) is ejected to one side of the folding unit 6.

The folding unit 6 is configured to stack the plurality of webs 7 sent from the web conveying device 5 and eject desired fold sections by longitudinal cutting, longitudinal folding using a triangular plate 26, lateral cutting, and/or lateral folding. An air blower (not shown) is provided near the triangular plate 26 and separates the webs 7 from the triangular plate 26 by blowing air. Folding unit drag rollers 27 for applying tension to the upstream webs 7 are provided forward of the triangular plate 26. Nipping rollers 28 for pulling the webs 7 downstream are provided inside the folding unit 6.

When the webs 7 are directly guided into the folding unit 6, without cutting with a slitter at the center in the width direction after printing, 16-page newspapers can be ejected to both sides. There is a device for switching and delivering the webs after printing at the printing units 3 a and 3 b for color printing to any position. This device, however, is not illustrated. To increase the number of pages, another web 7 is introduced from an adjacent printing unit. When the number of pages is small, e.g., when three of the printing units 3 are used, the path to the folding unit 6 of a web 7 printed at a printing unit 3 differs depending on which three printing units 3 are selected.

In this way, the lengths of the webs 7 from the printing units 3 to the folding unit 6 may vary depending on the operating pattern. When the tension associated with the web 7 varies, the degree of extension of the web 7 changes. Therefore, the length of the web 7 from the printing unit 3 to the folding unit 6 varies.

If the length of the web 7 from the printing unit 3 to the folding unit 6 varies in this way, the cutting position of the folding unit 6 changes. Therefore, the web 7 cannot be cut at a predetermined position.

The web offset press according to this embodiment includes compensator rollers 53 for changing the running-route length of the webs 7 and adjusting the cutting positions. Each compensator roller 53 is equipped with moving means 52 for moving it, supporting means, and a position detecting device, such as a potentiometer.

Next, the structure of the reel stand unit 1 will be described in detail. FIGS. 2A to 2F are schematic views illustrating the steps of the process of paper splicing according to the present method. In this method, a flying paster that carries out paper splicing while running a reel is used. As shown in FIG. 2C, in this method, a detachable motor 12 that is connected via an acceleration roller 11 is provided at the shaft end of a reel shaft as means for accelerating a new reel 10B. An air brake 13 for restricting and braking the reel shaft with air pressure is provided as means for braking the rotating of an old reel 10A and controlling the amount of the web fed out from the old reel 10A. The braking force of the air brake 13 is controlled by the air output from an air converter (not shown). The air converter converts the control output from the web offset press control unit 9 to the air output. The web offset press control unit 9 outputs a control output corresponding to operating conditions, such as reel diameter, by feedback control based on the deviation of a target tension and the actual tension.

First, in a normal operating state, as shown in FIG. 2A, the web 7 is fed out from the reel 10A. When the winding diameter of the reel 10A feeding out the web decreases, as shown in FIG. 2B, an arm 15 supporting a new reel 10B and the old reel 10A is turned to a predetermined paper-splicing preparation position, as shown in FIG. 2C. At the same time, a paster arm 16 is lowered to push a paster roller 17 provided in a freely rotatable manner on the paster arm 16 against the web 7. The new reel 10B is accelerated by the motor 12 by connecting the acceleration roller 11 to the reel shaft of the new reel 10B. The circumferential speed of the new reel 10B is controlled such that it matches the target speed set with reference to the line speed (the running speed of the web 7).

When the circumferential speed of the new reel 10B reaches the target speed, the web 7 is pushed against the new reel 10B by the paster roller 17 to adhere the web 7 to the new reel 10B with double-sided tape (described below) prepared on the surface of the new reel 10B (paster). Then, a cutter 18 provided on the paster arm 16 is activated to cut the upstream side of the adhered section of the web 7, as shown in FIG. 2D, to separate the web 7 from the old reel 10A. Immediately after this, the connection of the motor 12 driving the new reel 10B is released, and air is sent into the air brake 13 at the reel shaft end of the new reel 10B to start torque control. Subsequently, as shown in FIG. 2E, the arm 15 is turned to set the new reel 10B to an operating position. Then, as shown in FIG. 2F, the remaining core of the old reel 10A is exchanged with a new reel 10D.

FIG. 3 illustrates a state of the web 7 bonded with double-sided tape. A web 7B fed out from the new reel 10B is spliced with double-faced tape 19 to a web 7A fed out from the old reel 10A, which is the running paper. According to the related art, the cutting position for the cutter 18 from the double-sided tape 19 is approximately 2,400 mm. In this embodiment, the cutting timing of the cutter 18 is controlled by the web offset press control unit 9, and cutting is performed such that the tail length L is smaller than or equal to a predetermined length.

The length of the tail length L is set smaller than the minimum distance between driving rollers used in the device for conveying the web 7. More specifically, the length is set smaller than the distance between the blanket cylinders 24 of the printing unit 3 and the distances between the printing-unit drag rollers 25 near the outlet of the printing unit 3, the folding unit drag rollers 27 in front of the triangular plate 26 disposed at the inlet of the folding unit 6, and the nipping rollers 28 in the folding unit 6.

In this embodiment, the distance between the blanket cylinders 24 of the uppermost printing unit A, which perform black printing, of the printing unit 3 a and the printing unit B, which performs cyan printing, is the smallest (for example, 470 mm). The cutting timing of the cutter 18 is controlled by the web offset press control unit 9 such that the tail length L is smaller than this distance. More preferably, the tail length L is 323 mm or larger, which is the sum of a margin L1 (for example, 110 mm) and a cutter-to-brush distance L2 (for example, 218 mm) set by taking into consideration the response speed, maximum speed, error, and distance that reliably enables paper splicing. It is preferable to set the tail length L to 460 mm or smaller, which is slightly smaller than the distance between the blanket cylinders 24 of the printing unit A and the printing unit B, by taking error into consideration.

As shown in FIG. 4, the web offset press control unit 9 is capable of controlling the cutter 18 such that the tail length L is changed freely on the basis of the prepared length, the cutter delay time, and the cutter-to-brush distance L2, which are input parameters. These parameters are input by the user to appropriately change the tail length L.

With the rotary printing press having such a structure according this embodiment, the timing of the cutter 18 of the paster arm 16 is controlled by the web offset press control unit 9 to perform cutting such that the tail length L is smaller than or equal to a predetermined length. Therefore, in this embodiment, since the tail length L is smaller than the distance between the blanket cylinders 24 of the printing unit A and the printing unit B of the printing units 3, which is the minimum distance between driving rollers, the double-sheeted web 7 does not simultaneously stretch over two blanket cylinders 24. Of course, the web 7 does not stretch over two other driving rollers (blanket cylinders 24, printing-unit drag rollers 25, folding unit drag rollers 27, and nipping rollers 28).

As a result, the paper feeding force and paper pulling force increase, the property of the paper changes due to halving of the amount of water absorption of and the amount of ink on the running paper, and an increase in the rattling of the driving system is prevented. Therefore, stable registration can be carried out in the printing units 3, and thus printing quality can be improved. Furthermore, stabilization of cutting position, stabilization of web conveying, etc. can be achieved.

The driving rollers described in this embodiment are merely examples, and the present invention may be applied to a printing press having driving rollers with different structures, e.g., the blanket cylinders and the impression cylinders, which face each other and have a web passing therebetween, function as driving rollers. 

1. A printing press comprising: a reel stand unit configured to bond a web fed out from an old reel to a new reel and continuously feed paper by splicing paper from the old reel to the new reel, wherein the distance in the length direction of an overlapping section of the old reel and the new reel spliced by the reel stand unit is smaller than the minimum distance between driving rollers provided in the printing press.
 2. The printing press according to claim 1, further comprising: a cutter configured to cut the old reel spliced to the new reel; and a control unit configured to control the cutting timing of the cutter, wherein the control unit controls the cutting timing of the cutter such that the distance in the length direction of the overlapping section of the old reel and the new reel is smaller than the minimum distance between the driving rollers provided in the printing press.
 3. The printing press according to claim 2, wherein the control unit determines the cutting timing of the cutter on the basis of at least one of cutter delay time, preparation length, and a cutter-to-brush distance.
 4. A splicing method for a reel stand unit configured to bond a web fed out from an old reel to a new reel and continuously feed paper by splicing paper from the old reel to the new reel, the method comprising: cutting the old reel after the old reel is bonded to the new reel such that the distance of an overlapping section of the old reel and the new reel is smaller than the minimum distance between driving rollers provided on a path where the web passes until the web is finally cut. 